In EP-A-O,116,948, EP-A-O,153,152 and in U.S. Pat. Nos. 4,593,029 and 4,670,434 there are described a number of imidazo[2,1-b]quinazolinones as phosphodiesterase inhibitors having positive inotropic properties. Analogous compounds are also disclosed in J. Med. Chem., 30, pp. 303-318 (1987) and 31, pp. 145-152 (1988).